From what I've seen in my commercial blinds and fields, the Benellis and Berettas are the most reliable semi-autos out there. With the Beretta offering gas operation's lower recoil and higher maintenance/cleaning, and Benelli's inertia system's lower maintenance reuirements coming at the cost of somewhat greater recoil and susceptability to human error (screwing with the bolt and not getting its face rotated back into the locked position it closes to if not interfered or fooled with is far and away the leading cause of Benelli "malfunction").
In my hands, the two guns feel quite different, and I prefer the Benelli's. But if the Beretta felt more lively in hand or I were a serious clays shooter (or particularly recoil sensitive), I'd probably favor the Beretta.
And, were it me, I'd also be looking at the less expensive Benelli-made-for-Beretta inertia-operated Pintail.
(Please know the above observations come from a fellow who enjoys the prejudices of having shot one or the other or both of the same two Benellis, a 12ga SBE and 20ga Montefeltro, virtually every open season day since their early HK import.)
I have the SBE II which is quite similiar. It feels very comfortable and I have not noticed a great deal of perceived recoil. My buddy has the 391 and it is nice as well but a little heavier and to me it is for a larger shooter.
I recently purchased the M2 with the comfort stock. So far I love it. It has less recoil then my 870, it's only 7.2lbs. and is very fast. I have used it several times at the skeet field and once while goose hunting over water. I got my first triple.
i own both. the m2 is great. the only problem with it is it tears up the brass on kent shells will chamber others brands perfect ! the beretta i have is a 390 silver mallard it will shoot anything. close your eyes and pick one.
I?ve owned both of these in the 3 ? inch model. I prefer the 391 because it works for me better and a hunting buddy prefers his SBE. Here is my take on them:
The Berretta is a gas operated gun so it doesn?t kick quite as bad but it is a little heavier and it requires a little more maintenance than the inertia gun. To me it swings better and since it has less recoil I can get back on a bird quicker. My 391 feels a little beefier to me which I prefer. I do find I need to keep the action well maintained but when I do it is smooth as silk. The Benelli is lighter but like I said it kicks a little more. The stock is smaller than the 391, the inertia system works great and doesn?t require as much cleaning.
You have advantages and disadvantages in both guns but in the end either one is a great gun, it all comes down to which fits your shoulder better. If it is possible go to a range and put a box of shells through each one then you?ll know.